Recently, in the field of postproduction which edits the video data obtained from a video camera, a nonlinear editing system which uses a disc as a recording medium for recording the data of materials has been proposed. There are various types of edit processing as an editing processing performed in the nonlinear editing system. For example, they are the video edit processing for combining a plurality of materials to produce a desired video program, the composite processing for composing a plurality of materials by key signal, the special effect processing for applying the special effects to materials, and so on. Generally, the video edit processing is performed at an editing device, the composite processing is performed at a video switcher, and the special effect processing is performed at a special effect device.
In recent years, the development of a disc recording medium in its random access function makes it possible to access to a plurality of channels simultaneously. As a result, the edit processing for processing video data of a plurality of channels in real time has been desired. For example, in the television world in which television commercial messages are edited and produced or in the movie world in which movie programs are edited and produced, it is desired to use a dozens of materials to several hundred materials and to combine some different edit processings. More over, it is required to produce a complicated and high degree of edit resultant data by performing the several kinds of edit processing repeatedly.
To produce the complicated and high degree of edit resultant data, it is needed to control a dozen of materials to several hundred materials and to store the history of the edit processing.
However, in a conventional editing system, there is no device for controlling a lot of materials and no device for storing the edit history, so that the editing operation has became complicated. More specifically, an edit operator (hereinafter, referred to as “operator” shortly) can not remember the information that which material has been used and which edit processing has been performed when the edit resultant video data has been produced. Therefore, in the conventional editing system, the operator has managed the information by writing in a paper whenever the editing is performed. Further, in the case of the complicated edit processing such that a newly edit resultant video data is repeatedly produced from a plurality of edit resultant video data, the information of the editing history that which of materials is the final edit resultant video data produced from becomes large size of data, so that it has been impossible for the operator to manage the information by writing in a paper.
Also, in the conventional editing system, the operator needs to operate the device corresponding to the edit processing for each edit processing. Therefore, the edit works become complicated terribly. For instance, when two video data are composed, the operator needs to operate a control panel connected to a switcher device. When the special effect is applied to video data, the operator needs to operate a key board of the special effect device. There has been a problem that the device to be operated is changed in accordance with the edit processing so as to take much time to edit.